This is a phase II study to evaluate the safety and efficacy of azithromycin as treatment for encephalitis due to Toxoplasma gondii in persons with AIDS who have been unresponsive to or intolerant of treatment with sulfadiazine and pyrimethamine, or currently used alternatives. Azithromycin, a 15-membered ring macrolide, has been demonstrable in in vitro activity superior to the related antibiotic erythromycin against H. influenzae, N. gonorrhoea, and Legionella pneumophila and has activity as well against Mycobacterium avium-intracellulare (MAI) and T. gondii. The protection provided by oral administration of azithromycin against death due to toxoplasmic encephalitis in a murine model suggests that azithromycin in humans may be an alternative therapy for toxoplasmosis. Clinical trials of azithromycin for the treatment of opportunistic infections in AIDS patients are in progress. There has been a small but consistent reduction in bacteremia in patients receiving monotherapy with azithromycin for MAI. However, there is still only limited experience to date with azithromycin as salvage therapy for patients with toxoplasmosis. This study will evaluate azithromycin in that population.